![QP framework](https://www.state-machine.com/img/qp_banner.jpg) > **NOTE:** If your company has a policy forbidding open source in your product, all QP frameworks can be [licensed commercially](https://www.state-machine.com/licensing), in which case you don't use any open source license and you do not violate your policy. --------------------------------------------------------------------------- # What's New? View QP/C++ Revision History at: https://www.state-machine.com/qpcpp/history.html --------------------------------------------------------------------------- # Documentation The offline HTML documentation for **this** particular version of QP/C++ is located in the folder html/. To view the offline documentation, open the file html/index.html in your web browser. The online HTML documention for the **latest** version of QP/C++ is located at: https://www.state-machine.com/qpcpp/ --------------------------------------------------------------------------- # About QP/C++ QP/C++ (Quantum Platform in C++) is a lightweight, open source [Real-Time Embedded Framework (RTEF)][RTEF] for building modern embedded software as systems of asynchronous, event-driven [active objects][Active] (actors). The [QP/C++] framework is a member of a larger [QP] family consisting of [QP/C], [QP/C++], and [QP-nano] frameworks, which are all strictly quality controlled, thoroughly documented, and [commercially licensable][Lic]. ## Safer Model of Concurrency The [QP] framework family is based on the [Active Object][Active] (**actor**) design pattern, which inherently supports and automatically enforces the following best practices of concurrent programming: - Keep data isolated and bound to active objects' threads. Threads should hide (**encapsulate**) their private data and other resources, and not share them with the rest of the system. - Communicate among active object threads **asynchronously** via event objects. Using asynchronous events keeps the threads running truly independently, **without blocking** on each other. - Active object threads should spend their lifetime responding to incoming events, so their mainline should consist of an **event-loop** that handles events one at a time (to completion), thus avoiding any concurrency hazards within an active object thread itself. This architecture is generally **safer**, more responsive and easier to understand and maintain than the shared-state concurrency of a conventional RTOS. It also provides higher level of abstraction and the *correct* abstractions to effectively apply **modeling** and **code generation** to deeply embedded real-time systems. ## Hierarchical State Machines The behavior of active objects is specified in QP/C++ by means of [Hierarchical State Machines][HSM] (UML statecharts). The framework supports manual coding of UML state machines in C as well as automatic **code generation** by means of the free [QM modeling tool][QM]. ## Built-in Real-Time Kernels The QP/C++ framework can run on bare-metal single-chip microcontrollers, completely replacing a traditional RTOS. The framework contains a selection of **built-in real-time kernels**, such as the cooperative QV kernel, the preemptive non-blocking QK kernel, and the preemptive, blocking QXK kernel that provides all the features you might expect from a traditional RTOS. Native QP ports and ready-to-use examples are provided for major CPUs, such as ARM Cortex-M (M0/M0+/M3/M4/M7). ## Traditional RTOS/OS QP/C++ can also work with a traditional RTOS, such as ThreadX, FreeRTOS, embOS, uC/OS-II and TI-RTOS, as well as with (embedded) Linux (POSIX) and Windows. ## Maturity With 60,000 downloads a year, the [QP] family is the most popular such solution on the embedded software market. It provides a modern, reusable architecture for embedded applications, which combines the active-object model of concurrency with hierarchical state machines. --------------------------------------------------------------------------- # Getting Started with QP/C++ The [QP/C++ Reference Manual](https://www.state-machine.com/qpcpp/) provides instructions on how to download, install, and get started with QP/C++ quickly. The [AppNote: "Getting Started with QP/C++"][AN] contains also a tutorial, in which you build a simple "Blinky" application. --------------------------------------------------------------------------- # QP/C++ Licensing QP/C++ is licensed under the increasingly popular [dual licensing model][Lic], in which both the open source software distribution mechanism and traditional closed source software distribution models are combined. > **NOTE:** If your company has a policy forbidding open source in your product, all QP frameworks can be [licensed commercially][Lic], in which case you don't use any open source license and you do not violate your policy. --------------------------------------------------------------------------- # QP/C++ Documentation The **QP/C++ Manual** is located online at: https://www.state-machine.com/qpcpp --------------------------------------------------------------------------- # How to get help? - [Free Support Forum](https://sourceforge.net/p/qpc/discussion/668726) - [Bug Reports](https://sourceforge.net/p/qpc/bugs/) - [Feature Requests](https://sourceforge.net/p/qpc/feature-requests/) - [Quantum Leaps website](https://www.state-machine.com) - [Quantum Leaps licensing](https://www.state-machine.com/licensing) - [info@state-machine.com](mailto:info@state-machine.com) [RTEF]: [QP]: [QP/C]: [QP/C++]: [QP-nano]: [QM]: [Active]: [HSM]: [Lic]: [AN]: